(CNN)I haven't felt quite this sad since November 22, 1963, when I was an eighth grader and my hero John Kennedy was killed. The shock and the sadness from this election feel like a gash in the heart of our democracy, and it will take many, many years to heal the wound. That's partly because Hillary Clinton has lost the presidency by winning the popular vote, an anomaly that is only possible under America's odd system of electoral votes, which has anointed her opponent the victor.

Charles Kaiser

But it's also because, for the last eight years, we have been led by a president of amazing intelligence, and subtlety, and grace. As the son of an American mother and a Kenyan father, his election alone made America glow with a bracing new feeling of inclusiveness.

Then he gave health insurance to 20 million people who didn't have it before, he made marriage equality a reality through his appointments to the Supreme Court, he presided over the most rapid economic recovery any developed country experienced after the financial crisis, and he negotiated the only deal with Iran that could delay that country from building the bomb for at least 10 years --without firing a shot.

Obama also managed to keep his cool through the rudest and fiercest opposition any president has faced in many decades -- much of it from our new president-elect, the rest from Republican leaders of the House and Senate, some of whom vowed to try to destroy his presidency on his very first day in office.

Barack Obama transformed America's image abroad. At home, he gave millions of black people and Latino people and gay people more respect than they had ever felt from any other occupant of the White House.

Now all Obama's accomplishments are at risk, partly depending on how many Supreme Court justices Trump gets to appoint, and how much they value "religious liberty" over equal rights.

I don't know if Donald Trump is truly a racist in his heart. But I do know that he began his real estate career by excluding black tenants from his properties, that he tried to delegitimize Obama for years by pretending he wasn't a real American, and that he blew dog whistles for white supremacists and vicious anti-Semites throughout his presidential campaign. It is hard to digest the enthusiasm of white supremacists like David Duke for this event: "This is one of the most exciting nights of my life... make no mistake about it, our people have played a HUGE role in electing Trump."

Today Trump's election is being celebrated, most enthusiastically abroad by Vladimir Putin and his parliamentary allies, and by Muslim extremists across the Middle East.

The situations aren't the same, but I watched this election through the lens of "The Cost of Courage," the book I published last year about one French family who fought the Nazis when they occupied Paris.

I will not forget what it was that kept the heroes of my book strong and courageous and proud through four years of Germany's occupation. These remarkable men and women in their twenties realized right away that the only thing that could give their lives meaning in the face of this catastrophe was a battle to expel their occupiers. They did the only thing they could: They joined the French Resistance, and eventually they triumphed.

So yesterday it was appropriate for all of us who worked and prayed and organized for Hillary Clinton's election to pause and mourn, and to shed a tear for what feels to us like a wounded America. But today we must rise again, to organize and fight harder and smarter than we ever have. Because Hillary was exactly right in her concession speech: None of us must ever "stop believing that fighting for what is right is worth it."